Electrosurgical techniques have come into widespread and accepted use in both open and minimally invasive surgical procedures for cutting or coagulating tissue and controlling bleeding or fluid loss through cauterization.
Presently, electrosurgical instruments are of two general types: monopolar and bipolar. A monopolar electrosurgical system includes an instrument comprising an electrode that is conductively connected to the active terminal of a monopolar RF generator. A passive or return electrode in the form of a pad is conductively connected to the generator's return terminal. The pad is placed beneath the patient adjacent the site where the electrosurgical procedure is being performed. In use, current passes from the generator's active terminal to the electrosurgical instrument, through the patient's body to the pad and back to the return terminal of the generator. Monopolar electrosurgical instruments are used primarily for electrosurgical cutting of tissue (as opposed to the mechanical cutting of tissue) and provide for a generally wide-reaching coagulation.
In contrast, bipolar electrosurgical systems include instruments which have both a positive and negative electrodes on the instrument itself, which electrodes are connected to the positive and negative terminals of a bipolar RF generator. Bipolar electrosurgical scissors are disclosed in the co-pending application Ser. No. 399,421, filed Mar. 7, 1995 and Ser. No. 593,148, filed Feb. 21, 1996. In the instruments disclosed in these applications, each blade of the scissors includes both a positive and negative electrode separated by an insulation layer to prevent shorting between the two electrodes. Other bipolar electrosurgical scissors are shown in Rydell U.S. Pat. No. 5,352,222, Eggers U.S. Pat. No. 5,324,289, and EPO Published Application 717 966 A1. Bipolar electrosurgical instruments generally provide the surgeon with greater control of the path of the RF energy through the patient, as the RF energy generally passes only through the tissue located between the electrodes of opposite polarity on the instrument, and not otherwise through the patient's body. Thus, bipolar electrosurgical instruments may provide for a more refined surgical technique and more predictable current flow.
There are often situations during the course of a single surgical procedure in which the use of both monopolar and bipolar electrosurgical instruments has its advantages. Consequently, RF generators are available that provide for generation of both monopolar and bipolar RF energy, for example, the Valley Lab Force 2 RF generator. This combination generator includes two bipolar terminals and active and passive monopolar terminals, and it is contemplated that two different types of instruments, monopolar, and bipolar, can be connected to the generator simultaneously. However, such a system requires the surgeon to have both a monopolar and bipolar instrument at hand, rather from a single instrument that performs both monopolar and bipolar procedures.
More recently, an adapter for connecting a bipolar instrument to the monopolar active output of an RF generator has been proposed, see U.S. Pat. No. 5,573,424 to Poppe. While the same instrument can be used for both monopolar and bipolar electrosurgical surgery using this adapter, the Poppe device still requires that the instrument be unplugged and the adapter removed or attached before switching the instrument between the bipolar terminals and the monopolar active terminal of an RF generator.
Accordingly, it is an object of the present invention to provide an electrosurgical system, instrument and cable that permits both bipolar electrosurgical techniques and monopolar electrosurgical techniques to be performed with the same instrument without having to disconnect the instrument from the RF generator. More specifically, it is an object of the present invention to provide an electrosurgical system, instrument and cable in which the instrument may be simultaneously connected to both the active terminal of a monopolar RF generator and to the positive and negative terminals of a bipolar RF generator, so that the instrument can be used as either a monopolar or bipolar instrument merely by use of a switch associated with either the RF generator or the instrument.
It is a further object of the present invention to provide an electrosurgical instrument that can be used as both a bipolar instrument and a monopolar instrument without having to disconnect the instrument from the RF generator, merely by use of a switch associated with any of the RF generator, cable, adapter, or instrument.
It is an additional object of the present invention to provide a conductor cable for a bipolar instrument that allows the instrument to be used as both a monopolar and bipolar instrument.
It is a further object to provide an electrosurgical system and cable that automatically switches the instrument into contact with the monopolar active or bipolar terminals of an RF generator based upon the sensing of either monopolar or bipolar current from the RF generator.